The objective of this pilot project is to continue the characterization of the tuberculosis model in rhesus monkeys. We previously found that high dose inoculation of Mycobacterium tuberculosis H37Rv produced lethal lung disease within five weeks while low dose inoculation produced chronic disease. To extend this study we have inoculated four monkeys with M. tuberculosis (Erdman strain). Animals received between 100,000 and one million organisms by intrabronchial inoculation. Two animals that survived seven and 10 weeks developed extensive necrotizing granulomatous lesions in the inoculated half of the lung with spread to the contralateral lung, bronchial lymph node, liver, and kidney. Monkeys developed clinical signs of dyspnea, coughing, anorexia, and weight loss 4-6 weeks after inoculation. Skin testing with Old tuberculin became mildly positive after 5 weeks while PPD skin tests remained negative. Two other animals have become long term survivors as observed previously by us in animals inoculated with low dose M. tuberculosis H37Rv. Characterization of this model continues. Results contradict old literature and indicate that tuberculosis in rhesus monkeys may present as a chronic disease based on the dose of the inoculum. This suggests that future studies using low dose inoculation will be feasible in SIV-infected monkeys to study tuberculosis as an